ДАТЧИК ДАВЛЕНИЯ НА ПОВЕРХНОСТНЫХ АКУСТИЧЕСКИХ ВОЛНАХ С ЗЕРКАЛЬНОЙ ТОПОЛОГИЕЙ

Предложена новая конструкция датчиков давления, реализующая зеркальную топологию чувствительного элемента. Применение линий задержки позволяет создавать пассивные устройства, работающие на больших дальностях. Предлагаемое решение расширяет область применения зеркальных топологий для измерений давления. The liquid and gas pressure sensor is one of the most required sensors. Usually, resonator circuits are used in the passive wireless sensors based on surface acoustic waves. Wide application of pressure measurements resonators is caused by their small dimensions and, accordingly, by possibility to choose the part with low irregularity of parameter on the membrane (first of all a surface acoustic waves velocity). The sensitive elements based on surface acoustic waves delay lines have bigger linear dimensions than those with resonators. However, delay lines are less sensitive to irregularity of surface acoustic waves velocity distribution along acoustic way, and in practice to reach a long distance with a considerable number of random echo it is necessary to provide the significant (up to 4 |xs) delay of the sensor information response. The paper presents a new design, which implements the mirror topology of the sensitive element of pressure sensors. The use of delay lines allows the creation of passive devices operating at long ranges. The proposed solution extends the field of application of mirror topologies for pressure measurements.

Implementation of Simultaneous Multi-Parameter Monitoring Based in LC-Type Passive Wireless Sensing with Partial Overlapping and Decoupling Coils

Inductor–capacitor (LC) passive wireless sensors are widely used for remote sensing. These devices are limited in applications where multiparameter sensing is required, because of the mutual coupling between neighboring sensors. This article presents two effective decoupling techniques for multiparameter sensing, based on partially overlapped sensors and decoupling coils, which, when combined, reduce the mutual coupling between sensors to near zero. A multiparameter LC sensor prototype with these two decoupling mechanisms has been designed, simulated, and measured. This prototype is capable of simultaneously measuring four parameters. The measurements demonstrate that the changes in capacitance in one individual sensor do not affect the measurements of the other sensors. This principle has been applied to simultaneous wear sensing using four identical wear sensors.

Wireless Readout of Multiple SAW Temperature Sensors

It has since long been known that surface acoustic wave (SAW) devices, resonators as well as delay lines, can be used as passive wireless sensors for physical quantities, like temperature and pressure, as well as gas sensors or identification-tags (ID-tags). The sensors are robust, work passively without a battery, can be applied at high temperatures, and provide a high resolution. Nevertheless, if the devices are used wirelessly in an industrial environment, several constraints have to be taken into account, especially when more than one quantity or device needs to be measured at the same time. The paper addresses the challenges that must be tackled when establishing multi-sensor-wireless-readout for industrial applications. Major issues here are the legal regulations for industrial, scientific and medical frequency bands (ISM-bands), as well as sampling time and costs, which impose severe restrictions to any system design. We describe several design approaches and their constraints. We successfully designed sensors based on reflective delay lines that allow the parallel readout of four independent temperature sensors in the 2.45 GHz ISM-band. These devices were fabricated and positively tested, demonstrating the applicability of SAW sensors for industrial applications.

Wireless Readout of Multiple SAW Temperature Sensors

It is since long known, that SAW devices, resonators as well as delay lines, can be used as passive wireless sensors for physical quantities like temperature and pressure as well as gas sensors or ID-Tags. The sensors are robust, work passively without battery, can be applied at high temperatures and provide a high resolution. Nevertheless, if the devices should be readout wirelessly in an industrial environment, several constraints have to be taken into account, especially when more than one quantity or device needs to be measured at the same time. The paper addresses the challenges that have to be tackled when establishing multi-sensor-wireless-readout for industrial applications. Major issues here are the legal ISM-band regulations, as well as sampling time and costs, which impose severe restrictions to any system design. We describe several design approaches and their constraints. We have successfully designed sensors based on reflective delay lines that allow the parallel readout of four independent temperature sensors in the 2.45 GHz ISM-band. These devices have been fabricated, positively tested and demonstrate the applicability of SAW sensors for industrial applications.